:-[ ?
Which pakset(s) are you using; and is this 11.12 or another version?
11.12, and pak128 standard (older nightly and current nightly, as well as some other versions I have tested...) and pak128.cz and pak64.japan--
Does this occur with any map creation settings?
Those that I have tried, yes (disabling city generation seems to let it come further.)
Have you tried it? Should be easy to recreate - mostly any standard pak. Make new game, and it will crash (sometimes immediately and sometimes after generation progressing a bit).
Apologies: I have not had a chance to work on bugs in the last few days as I was finishing other matters, but I shall look into this presently.
Now found and fixed - thank you for the report.